The present invention relates to an apparatus for simultaneously producing an inner ring and an outer ring from a single workpiece including an annular portion and a smaller annular portion concentrically integrally projecting from the annular portion, the workpiece being formed by cutting a round bar to a specified dimension and pressing the resulting piece by forging machine.
It is already known to produce rings for example for the manufacture of ball bearings by a method other than cutting, namely by applying an axial shearing force to a blank prepared by press work and including large and small annular members in a steplike shape. With the known method, the large and small annular members joined together side by side in the axial direction are separated from each other at the junction. However, the method has the following drawbacks. One of the separated annular members has an outwardly projecting flange on the outer periphery of its end, whilst the other member has an inwardly projecting flange on the inner periphery of its end. Thus the method requires a subsequent process to remove the flanges to provide smooth peripheral surfaces having no projections. In addition, one of the separated annular members is forced into the die, followed by like annular members during continuous operation, with the result that a series of like members adhere to each other because of the hot work environment. The method therefore entails the necessity of separating these members after cooling.